Ethernet Peer-To-Peer Communication With Model 353 And Procidia i pac Controllers

Transcription

1 iemen Energy & utomation pplication ata Ethernet Peer-To-Peer Communication With odel 353 nd Procidia ipac Controller Rev. 1 July Ethernet i a leading form of network communication that i often employed on indutrial proce network. ata i exchanged between network-connected, Ethernet-enabled proce controller, peronal computer, and field intrument to control and monitor a proce. Thi data can be hared throughout a company and, by way of the Internet, it can be made available to remote location almot anywhere in the world. Preented here i an overview of peer-to-peer communication on a private Ethernet network that include odel 353 Proce utomation Controller or Procidia ipac Internet Control ytem. There are private and public network. In thi paper, we are concerned with the private network. private network ha acce intentionally retricted to pecific individual, uually within a company or within one pecific area within a company. Private network can be linked for efficient exchange of data. Open acce characterize a public network. The Internet i an example of a public network where anyone with the requiite computer and oftware can log on. In thi paper, we dicu what Ethernet i, decribe building a network, and briefly introduce network addreing. Next, controller configuration and Ethernet function block are dicued. Finally, controller firmware and hardware requirement are lited. The cope of thi paper i limited to introductory material. However, the Reference ection on the lat page ha a lit of book and manual that provide in-depth information about the above topic plu network ecurity, wiring, and troublehooting. iemen offer training clae that include configuring a controller for Ethernet operation; ee the Reference ection. The final word though belong to your company network adminitrator. He or he i a primary ource of additional information about network ecurity, deign, IP addreing, and other critical network iue. WHT I ETHERNET? Ethernet i imply an agreed upon et of rule that decribe how device will exchange meage. Thee rule are publihed in IEEE pecification.3 and they decribe in detail the critical apect of Ethernet communication including the format of the data packet and the phyical interconnection (cable and connector). The Ethernet form ued by the above controller i odbu TCP/IP (Tranmiion Control Protocol/Internet Protocol). 1 eage are correctly addreed and routed by IP; TCP inure that all packet of data are received correctly. imply tated, odbu TCP/IP i odbu communication encapulated in an Ethernet TCP/IP wrapper. Before delving further into Ethernet, ome odbu characteritic need to be mentioned. odbu i a common communication protocol upported by many intrument manufacturer. odbu communication i baed on one mater device and one or more lave device, each lave having a unique 1 odel 353 and Procidia are capable of odbu TCP/IP and HTTP over 1BaeT and 1BaeT.

2 PB1 COE 1 UNIT identity or addre. Uually, the mater i a PC or PC. The lave device are controller, lave PC, and field intrument. The odel 353 and Procidia ipac are lave controller. Only the mater can initiate communication and it can iue either a data requet or a write data command. The odbu command contain: the unique addre of the lave to which the meage i directed, the command function code, the tarting regiter addre, and the number of regiter affected. The lave recognize it addre, perform the command operation, and end a repone. The repone i either the data requeted or a reply that it received the write command. The tarting regiter addre and the number of regiter affected pecifie the location and ize of the data. On a odbu network, the mater mut wait for the reply before iuing another requet. Thi architecture doe not allow peer-topeer communication between lave device. Unlike odbu, Ethernet communication upport peer-to-peer communication becaue it permit all device, known a hot in Ethernet parlance, to initiate communication. In Figure 1, three hot are connected together through a hub forming a network. ny hot can end a meage through the hub to the other hot. However, only one hot at a time can end a meage. If two hot do end meage at the ame time, the meage collide and become unreadable. Colliion avoidance i built into Ethernet through the ue of C/C (Carrier ening ultiple cce with Colliion etection). When a hot need to end a meage, it firt liten to the network, to determine if another hot i ending a meage. fter a hort period of network inactivity, the hot end it meage. If another hot attempt to end a meage at the ame intant, both top and wait a random length of time before attempting to re-end their meage. ince each hot wait time i random, the previou communication colliion i unlikely to be repeated. However, each colliion and enuing wait time reduce the volume of traffic that can flow on the network. The deign of the network can reduce the probability of colliion and ignificantly increae network traffic. Hub TC53. P P 1 odel 353 odel 353, ddre 3 Control Room HI, ddre 1 Ethernet Enabled Field evice, ddre G4a FIGURE 1 Hub-Baed Ethernet Network The 353 and ipac controller are odbu lave, by deign, and repond to odbu command. To enable the controller to initiate Ethernet peer-to-peer communication, Ethernet communication function block are included in firmware verion. and higher. There are three function block that initiate communication: IE (nalog Input for Ethernet communication), IE (igital Input for Ethernet) and CIE (Coil Input for Ethernet). Each block iue a data requet command. The compliment to the above block are the OE (nalog Output for Ethernet) and OE (igital Output for Ethernet) function block. Thee block do not initiate communication. They map data to the

3 controller odbu regiter (memory location) where the data are tored. ata in the odbu regiter are available to the network. Note that controller cannot initiate write command. Thi privilege belong to an operator who can initiate action through an HI, uch a a Procidia itation. BUIING NETWORK The manner in which hot are connected together to create a network i referred to a the network topology. Thi include the cabling of the network-connected hot and the ue of hub, witche, router and gateway to accommodate that cabling and create the deired network tructure. Figure 1 and how imple network. Figure 3 how two network connected through a router. Thee arrangement or topologie will be dicued in thi ection. Each hot connected to a network mut have a unique identifier known a an addre -- equivalent in purpoe to your home addre. In Figure 1, the addree are 1,, and 3. meage can be ent, for example, from the HI at addre 1 to the controller at addre 3; the field intrument at addre will receive the meage but ignore it ince the meage wa not addreed to it. Thi i point-to-point or peerto-peer communication. Broadcat communication allow a hot to end a meage to all other networkconnected device. any people will participate in the deign of the network. Your company network adminitrator will play a primary role by examining ecurity iue, aigning addree, and deciding other critical iue. Proce engineering will identify the equipment that i to be connected to the Ethernet network. Company management may be intereted in connecting a network that link the purchaing and accounting department to the proce control network. If remote monitoring i required, an intranet, extranet, or the Internet may alo be connected. Network reliability and ecurity will be of immene concern to all involved. Ethernet Network with a Hub In Figure 1, a hub i ued to connect the controller, field intrument, and HI. The hub i imply a central point to which a number of hot, often a many a 8-1, can be electrically connected. Every meage ent by a hot i ent to every other connected hot but read by only the addreed hot. The hub ditribute the meage but, ince it i a paive device, it cannot direct the meage only to the addreed hot. pointed out earlier, a colliion occur when two hot try to end a meage at the ame intant. With only three hot, network performance i probably adequate. However, a additional hot are connected to accommodate plant or proce expanion, network performance uffer. ince only one hot at a time can acce the network and there are now more hot, network traffic increae, the number of colliion increae, and performance degrade. The ue of a hub to interconnect hot i generally not recommended. The olution i to replace the hub with a witch, alo known a a witching hub. Ethernet Network with a witch witch, like a hub, interconnect hot. However, the witch direct traffic more effectively ince it can read addree and route a meage directly to the addreed hot. In Figure, a meage ent by hot 1 to hot i not ent to hot 3 and 4. Indeed, at the ame time hot 1 and are communicating, hot 3 and 4 can be communicating. The witch iolate the imultaneou communication allowing an increae in network traffic while reducing meage colliion. 3

4 PB1 COE 1 UNIT PB1 COE 1 UNIT witch TC53. P P 1 odel TC53. P P 1 odel 353 Ethernet Enabled Field evice, ddre odel 353, ddre 4 odel 353, ddre 1 Control Room HI, ddre 3 G4a Router or Gateway-Connected Network FIGURE witch-baed Ethernet Network router i ued to connect together network of the ame type, for example, two Ethernet network. Figure 3 how two router with built-in witche connecting a proce area network to an office area network. The office network include the purchaing and accounting department, and a web erver and gateway with a ecurity firewall for acce to the Internet. router can read an addre and route a meage to the proper network and to the addreed hot. In addition, a router iolate the network and can uually prevent a problem on one network from affecting other connected network. Network performance and reliability are ignificantly improved. gateway i a general term for device that link two network together, and the router i a member of the gateway cla. gateway i often able to connect two different type of network together, for example, connecting an Ethernet network to an IB N (ytem Network rchitecture) network. public network, uch a the Internet, can be connected to a private network through a gateway or a router. For information about configuring a gateway or router, refer to the manufacturer intallation manual. IP RE Thi ection introduce IP addreing. ddreing i a complex topic, particularly when everal network and ub-network are involved. Your company network adminitrator will upply hot addree, mak, ubnet addree, and gateway addree a needed. ddreing i an ineparable part of network deign. Every hot on a network need a unique addre. In Figure 1, addree 1,, and 3 were ued. The Internet Protocol (IP) ue a 3-bit addreing tructure. n example of an IP addre i Notice that the complete addre i written a four number in a dotted-decimal notation, i.e. the four decimal group are connected together by three dot. Each decimal number ha a range of to 55. 4

5 PB1 COE 1 UNIT PB1 COE 1 UNIT PC in Purchaing PC in ccounting Internet Web erver Office rea Network witch Router Note: Router/witch combination may be two eparate device. Gateway To/From Internet Proce rea Network Router witch G4a TC53. P P 1 odel TC53. P P 1 odel 353 Ethernet Enabled Field evice odel 353 odel 353 Control Room HI FIGURE 3 Ethernet Network with Router and Gateway portion of the complete addre repreent the network addre (netid); another portion the ubnet addre (ubnetid), on a more complex network; and a third portion the hot addre (hotid). However, it i important to remember that all four decimal number provide the complete addre. brief example of the ue of ubnet addree and ubnet mak i provided later in thi paper. If the network i not connected to another network, particularly the Internet, almot any IP addree can be aigned. However, the IN (Internet igned Number uthority) ha reerved three block of addree for private network. Thee reerved addre range hould be ued whether or not a connection to a public network i anticipated through or through or 1... through

6 default addre i provided by a 353 or Procidia controller. It can be ued in many application where the proce control network i not connected to other network. When a Window -baed PC i to be configured, make the needed entrie in the dialog box hown in Figure 4. Your network adminitrator can provide addree, ubnet mak, and other neceary information. FIGURE 4 ample Window TCP/IP Propertie ialog Box PEER-TO-PEER CONFIGURTION To configure peer-to-peer communication between controller, build each controller configuration a you normally would. Wherever an external analog value or point i to be exchanged over Ethernet, add an IE or OE function block to the configuration. Note that more than one IE block can requet data from a ingle OE block. ake a lit of each Ethernet analog block created and the loop where it i located for later connection. Where an external dicrete value or point i to be acquired over Ethernet, add a IE block. ince the IE block upport 16 point, it i likely that everal loop will need to connect to it. Create a eparate I/O icrete loop and place one IE block for each network-connected controller from which data or tatu will be obtained. ake a lit of each Ethernet dicrete input block created and the loop where it i located. Where a dicrete value i to be tored in the controller odbu regiter, add a OE block to the configuration. Note thi regiter location for later connection. 6

7 When finihed, return to each configuration and tie the Ethernet I/O block. Next, aign IP addree to each controller. The lat tep i to go through each IE and IE function block and et the ource IP addre and odbu regiter location. Ethernet Function Block The ETHERNET function block i ued to aign the controller IP addre and to et communication parameter. The ETHERNET function block i located under tation Function Block. IP RE (IP ddre) Each controller require a unique IP addre. Enter the addre aigned by the network adminitrator. lternatively, if thi i a private network, ue an addre from the block of reerved IP addree lited earlier in thi paper. IP K (ubnet ak) The ubnet mak i the method ued to identify meage that are addreed to member of a ubnet. ore than one ubnet can exit in the ame network. If the ubnet addre i , then ue IP mak If the ubnet addre i , then ue IP mak Your network adminitrator will provide the needed addree and mak. The following example of bit-wie logic illutrate how the ubnet mak work: IP ddre ( ) ubnet ak ( ) N bit logic ubnet ddre ( ) IP GTE (Gateway IP ddre) If the local network i iolated by a gateway, then the gateway IP addre need to be pecified. Typically, it i aigned the firt hot addre in the ubnet, e.g or gateway addre mut be aigned. If a gateway i not preent, the gateway field hould contain an unued addre within the hot ubnet (addre range). ETH PX (Ethernet uplex mode) The Ethernet uplex mode parameter pecifie how device (e.g. witche, router) communicate with each other. It i recommended to et ETH PX parameter to utomatic mode. When the hot regiter with the witch (or gateway), it etablihe the communication mode. The Full- uplex and Half-uplex mode option are available in the event that other hot on the network upport only one mode. Conult with the network adminitrator before making a election other than that recommended here. default controller addre i provided. One controller on a network can ue thi addre. unique addre will need to be aigned to each additional controller. 7

8 ETH RTE Thi Ethernet Rate parameter refer to more than the communication baud rate. It refer to the network wiring pecification and topology. ot hot can upport both Ethernet 1BE-T (1 mbp) and 1BE-T (1 mbp). et the ETH RTE parameter to utomatic. When the hot regiter with the witch (or gateway), it etablihe the baud rate for each connection. The 1BE-T and 1BE-T option are available for unique network topologie. Conult with the network adminitrator before making a election other than that recommended here. When uing a witch, each hot-to-witch connection can be et for either 1BE-T or 1BE-T. PP RTE (Peer-to-Peer Communication Rate) The Peer-to-Peer parameter pecifie in econd how often the controller iue a data requet command. IE Function Block The IE function block i ued to requet analog data from another controller on the network. In a typical application, a uperviory controller provide an external et point to a loop controller. Thirty-two (3) IE block are available per controller. Example: In a team powerhoue application, the plant mater controller regulate the main team header preure. ll boiler are connected to the main header and the header provide team to the plant. Each boiler controller relie on the plant mater to dictate the percentage of full capacity at which it hould be running. Thi value i the plant fire rate demand (FR). To tranfer the plant FR acro an Ethernet network, each boiler controller will contain an IE function block in the boiler mater loop. ee Figure 5. It replace the IN function block ued with traditional field wiring. The boiler controller will periodically iue a data requet command to get the latet plant FR. The plant mater controller will have the compliment OE block. The purpoe of the OE block i to provide a memory location for the plant FR value. The plant mater controller, being a odbu lave, will repond with the value located in the pecified odbu regiter. IP RE (ource IP ddre) The IP addre of the ource controller i required. 8

9 PB1 COE 1 UNIT PB1 COE 1 UNIT PB1 COE 1 UNIT witch G4a TC53. P P 1 odel TC53. P P 1 odel TC53. P P 1 odel 353 Plant ater Boiler 1 Boiler team Preure Boiler ater Boiler ater OE1 IE1 IE1 I/O icrete I/O icrete I/O icrete IE1 IE OE1 OE IE1 OE1 IE1 OE1 B REG (odbu Regiter) FIGURE 5 Ethernet Peer-to-Peer Communication Embedded within the odbu command i the tarting regiter addre and the number of conecutive regiter to be read. The function block aume that the data i in IEEE floating point format and it requet two regiter of data. ( regiter i 16 bit). For convenience, the tarting regiter for each OE i lited in the Uer anual under the IE function block ection. ata can be requeted from regiter other than OE block. For example, the proce, et point and valve variable can be read directly from the OC block. Be ure to elect the odbu regiter from the ynamic oop Floating Point ata (IEEE) and not the ynamic oop Integer ata. It i poible to requet IEEE formatted data from other hot that upport odbu TCP/IP protocol. The default hot odbu addre i 1. Important: The IE function block aume that data i in IEEE format and requet two regiter of data. RNGE When data i to be diplayed in the controller or itation faceplate, caling information i important. Thi information alo affect the performance of the PI and other loop function block. The tandard procedure i to aign the INCE, XCE, PP and ENGUNIT parameter of an analog input block. When the RNGE parameter i in utomatic mode, caling information come from the OE block in the ource controller. In anual mode, the caling information pecified in the IE function block parameter i ued. In the uto mode, the advantage of thi parameter i that any change made to the caling parameter of the ource controller are applied to all other controller in the network. It i good engineering practice to configure all range pointer. The default etting i anual mode. 9

10 Important: If requeted data doe not come from an OE block, et the RNGE parameter to anual and et the INCE, XCE, PP, and ENGUNIT parameter appropriately. ee the controller Uer anual. Note: ince data i tranferred in IEEE format, the value i not altered. OE Function Block The OE function block i ued to map analog data to the odbu regiter, to make it available to the network (i.e. the IE block in another controller). Thirty-two (3) OE block are available per controller. The OE block doe not contain caling information. If the aociated IE block i requeting caling information (Range i utomatic mode), then the OE range pointer mut be configured to an appropriate analog input or calar function block. Refer to the controller Uer anual for additional information about thi block. IE Function Block The IE function block i ued to requet dicrete data from a econd controller on the network. Thirtytwo (3) IE function block are available per controller. Each IE function block upport 16 dicrete point. eparate IE block i required for each controller from which data i requeted. Refer to the controller Uer anual for additional information about thi block. Note: In the 353, dicrete data i normally tored in the odbu coil. ince thi command iue a read regiter command, it cannot be ued to requet controller dicrete data. The CIE block iue the read coil data command. IP RE (IP ddre) The IP addre of the ource controller i required. B REG (odbu Regiter) Embedded within the odbu command i the tarting regiter addre and the number of conecutive regiter to be read. The function block aume that the data i in bit format and requet one regiter of data. ( regiter i 16 bit). For convenience, the tarting regiter for each OE i lited in the Uer anual under the IE function block ection. Important: The IE block aume that data i in bit format and requet one regiter of data. OE Function Block The OE function block i the compliment of the IE. Thi block map the dicrete output of other function block to the odbu regiter. Thirty-two (3) block are available per controller and 16 point can be configured per block. Refer to the controller Uer anual for additional information about thi block. 1

11 CIE Function Block The CIE function block i ued to requet dicrete coil data from another controller on the network. Thirty-two (3) CIE function block are available per controller. Each CIE function block can obtain up to 16 conecutive coil. There i no compliment block for the CIE. Refer to the controller Uer anual for additional information about thi block. odbu coil are memory location where dicrete data i tored in bit format. Coil are different than regiter and can be viualized a a different ector in memory. Coil have their own et of data requet and write command. Controller dicrete logic data i available a output of function block. In peer-to-peer communication, ue IE and OE block where needed to tranfer dicrete data. Thi method i recommended over uing the CIE block becaue, when uing the Graphical Configuration Utility, the controller configuration i more thoroughly documented. The CIE i available for completene and it allow acce to certain dicrete tatue that are not available via function block output. It may be of value, for example, to know if an alarm ha been acknowledged or that a controller i in run mode (tation coil 8). CONTROER FIRWRE N HRWRE REQUIREENT The following firmware and hardware item mut be intalled in a controller for it to operate on an Ethernet network. Procidia ipac Internet Control ytem evel B Controller Carrier (odel ipc-cc-b4) ipac Ethernet Communication Board Firmware v. or higher odel 353 Proce utomation Controller ounting Cae Option 4 with RJ-45 Ethernet connector (odel 353_4...) odel 353 Ethernet Communication Board Firmware v. or higher REFERENCE Teach Yourelf Networking in 4 Hour, att Hayden, Publihing, 1 Networking with icrooft TCP/IP, rew Heywood, New Rider Publihing Networking Complete, econd Edition, ybex, Inc., 1 Procidia ipac Uer anual, UiPC-1, Rev. 4 or higher odel 353 Uer anual, U353-1, Rev. 9 or higher iemen Controller Configuration Training Cla - t under Training@iemen, Intructor-ed, elect Proce Intrumentation from the drop-down box for the coure chedule and a link to the coure decription. lternatively, requet the bulletin titled iemen Technical Training, Proce utomation ytem, B6INT from: iemen Energy & utomation, Inc. Technical Training Center 11 umneytown Pike P.O. Box 9 pring Houe, P

12 Copyright, iemen Energy & utomation, Inc. Procidia, ipac, and itation are trademark of iemen Energy & utomation, Inc. Other trademark are the property of their repective owner. iemen Energy & utomation, Inc. aume no liability for error or omiion in thi document or for the application and ue of information included in thi document. The information herein i ubject to change without notice. Cutomer are urged to conult a iemen Energy & utomation, Proce Indutrie iviion ale repreentative to confirm availability and pecification. 1